Das Projekt "Field and laboratory studies of aerosol formation from halogenated precursor gases" wird vom Umweltbundesamt gefördert und von Technische Universität Berlin, Institut für Technischen Umweltschutz durchgeführt. This project was part of the HaloProc research unit on natural halogenation processes, and explored the impact of reactive halogen species on aerosol formation in field and laboratory experiments. Field studies were focused on the Lake King salt lake area in Western Australia. New particle formation events were frequently observed and characterized by measuring the temporal evolution of the submicron aerosol size distributions, and collecting aerosol samples for subsequent chemical analysis. 9 out of 11 measurement days in 2013 showed secondary aerosol formation with particle growth rates from 2.9 to 25.4 nm h^-1. Raman spectroscopy and ultrahigh resolution mass spectrometry revealed a contribution of organohalogen compounds (mostly organochlorine) to the secondary organic aerosol, however, organosulfate and organonitrate formation seemed to play a larger role in the studied environment. Nevertheless, a new experimental approach that made use of a mobile Teflon chamber set up above the salt crust and the organic-rich mud layer of various salt lakes directly linked new particle formation to the hypersaline environment of Western Australia. For more detailed process studies, these field results provided realistic scenarios and constraints for simulation experiments in the laboratory. Salt lake conditions were successfully simulated in aerosol chamber experiments and showed secondary aerosol formation in the presence of light and organic precursor compounds. The particle formation dynamics and the chemical speciation of aerosol samples, which were collected from the chamber experiments and analyzed by Raman spectroscopy and mass spectrometry, indicated a coupling of aqueous phase chemistry and secondary aerosol formation. In particular, the Fe(II) concentrations of the simulated salt lakes were a key control for the intensity of new particle formation. In saline environments with low pH values and high solar radiation, Fe(II) might be converted to Fe(III) in the presence of organic matter in a Fenton-like reaction, which can act as a major source for highly reactive OH radicals in the aqueous phase. On the one hand, this expands the potential oxidation pathways for organic compounds, which led to a larger chemical diversity. On the other hand, Fe(II)-controlled aqueous phase chemistry competes with secondary aerosol formation in the gas phase, which led to reduced particle formation in our experiments. While it is premature to fully incorporate these findings in chemistry box models, additional laboratory studies provided experimental data that will guide the development of model parameterizations, e.g., for the organic aerosol yield from the oxidation of organic compounds by chlorine and bromine, or for reactive bromine loss due to uptake in secondary organic aerosol. In conclusion, this project bridged gaps between field studies of halogen-influenced new particle formation in the real world and laboratory experiments within the HaloProc research u
Das Projekt "Sub project: Imaging Induced Seismicity at the KTB" wird vom Umweltbundesamt gefördert und von Universität Hamburg, Zentrum für Meeres- und Klimaforschung, Institut für Geophysik durchgeführt. The observation of naturally or artificially generated acoustic emissions (i.e., small earthquakes) by seismic networks is a powerful tool to image transport processes in the earth. During the injection experiments at the KTB a large number of events were observed. The precise spatio-temporal characterization of the seismic events is of utmost importance since all following interpretations (e.g., transport properties) rely entirely on this result. The localization of the events depends on the model used for the localization. The anisotropy of the KTB rocks is a well known feature but was not considered for the localization. Previous studies demonstrate that this leads to severe errors in the location of events. In this study we will first determine the anisotropic elastic features from the comprehensive KTB VSP data sets using 3-D anisotropic tomography for P- and S-waves. This step is essential for the localization. The obtained tomographic anisotropic 3-D model will then be used for the localization of the acoustic emissions of the 2000 and 2004 injection experiments. A newly developed technology based on reversed modelling or time reversed acoustic mirrors will be used to image the events. This techniques does not require picking of events and increases the detection level of the network owing to the stacking character of the method and allows to locate arrivals not visible in the individual seismograms of the network.
Das Projekt "Sub project: Hydrochemical and hydraulic properties of the continental upper crust at the KTB site" wird vom Umweltbundesamt gefördert und von Regierungspräsidium Freiburg, Abteilung 9 - Landesamt für Geologie, Rohstoffe und Bergbau durchgeführt. A constant rate pumping test of one year duration is planed to be carried out in the 4.0 km deep pilot hole of KTB. Watertable fluctuations in the pilot borehole and in the 9.1 km deep main borehole will be monitored as well. A wealth of data (pumping rate, watertable/ pressure, temperature, salinity/electrical conductivity, water samples,....) will become available, some even online. The first objective of the proposed project is to determine the flow system (type of aquifer model). From this deduced hydraulic model follow the hydraulic characteristics (such as: transmissivity, storage coefficient, fracture lengt/ width/aperture, permeability of fractures and matrix,....) describing the properties of the crystalline basement rocks in vicinity of the KTB pilot- and main hole. The length of the expect test radius is some 1000 m. The proposed project intends also to determine the degree of the hydraulic connection between the two holes (having a depth difference of 5.1 km). Additional information, such as water analyses, will be needed in interpreting the hydraulic data. A second major objective is the modelling of water-rock interaction (WRI) processes using the chemical data of KTB fluids. In particular the time series of chemical data will be used to model the kinetic and time dependent processes. We expect as well to see some breakthroughs of 'fresh, clean' crystalline basement water and another breakthrough resulting from fluid stored in the main hole and its surrounding.
Das Projekt "Sub project: Fault zone damage and chemical reactions at depth in the San Andreas Fault Zone: A study of SAFOD drill core samples" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum durchgeführt. The results of the first funding period, particularly the proof of several weakening and hardening mechanisms operating in the fault gouge of four SAFOD core samples (e.g. amorphous material, nano-scale pore spaces, dissolution-precipitation processes, intracrystalline plasticity) inspired a more detailed study of microstructures in order to specify the cause of mechanical weakness along the San Andreas Fault (SAF). Therefore we applied for and received four additional core samples from different depths and different distances to the fault contact. In particular, we will focus on: - The analysis of dominant microstructures in the new SAFOD samples. Based on our previous experience we will predominantly use the transmission electron microscopy (TEM). These studies have proven to be the most powerful tool for analyzing microstructures. The cutting of foils with the focused ion beam technique (FIB) allows identifying microstructures down to the nm scale without damage. - The observed microstructures will be interpreted in view of their implication for fault weakening mechanisms integrating previous results of the core samples from the first funding period. - The observed agglomeration of flocculated clay particles in previous samples calls for further detailed TEM investigations of clay minerals. - Some vein-calcites show evidence for intense intracrystalline plasticity (deformation twins and dislocation creep). We will measure dislocation and twin densities in calcite veins in the new sample set. The results will be used for stress estimations based on paleo-piezometric relationships. - First results of stable isotope analyses of vein calcites provide indications that the fluids were dominantly derived from deeper sources. We will further analyze stable isotopes with the aim to characterize the origin of fluids penetrating the fault gouge. - Mercury porosimetry and the BET gas adsorption methods will be used to measure the connected rock porosity pore volume and pore surface areas of our new samples. Porosity data will be used to roughly estimate permeability. - SAFOD microstructures will be compared to samples recently obtained from the Taiwan Chelungpu fault Drilling Project (TCDP).
Das Projekt "Subproject: The role of mantle plumes in the formation of Large Igneous Provinces: con-straints from noble gases" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum durchgeführt. Large igneous provinces (LIPs) are thought to have formed by magmatism resulting from decompressional melting of plume heads. Mantle plumes are upwellings of mantle material in focused conduits considered to originate from deep within the mantle. Plume heads are the leading ends of such upwellings. However, the evidence for this theory of LIP formation is mixed and has been challenged lately. In this context noble gas isotopes are important as a discriminator of deep-mantle origin because of the large and indicative isotope variations existing between the various terrestrial reservoirs. One of the main arguments for a plume origin of Continental Flood Basalt (CFB) magmas is excess 3He compared to MORB. High 3He/4He ratios have been found, e.g., in the Afar and Columbia River CFB provinces. Noble gas data from the Paraná-Etendeka LIP do not exist and the He isotope data available from the Tristan da Cunha hotspot are not meaningful. Thus we propose a noble gas study of samples from Tristan da Cunha, Etendeka and Paraná to constrain the mantle components involved in the formation of CFB and hotspot lavas and to shed some light on the role of plumes in LIP formation.
Das Projekt "Phosphorus transport along soil pathways in forested catchments" wird vom Umweltbundesamt gefördert und von Technische Universität Dresden, Institut für Bodenkunde und Standortslehre durchgeführt. Phosphorus (P) is an essential nutrient for living organisms. Whereas agriculture avoids P-limitation of primary production through continuous application of P fertilizers, forest ecosystems have developed highly efficient strategies to adapt to low P supply. A main hypothesis of the SPP 1685 is that P depletion of soils drives forest ecosystems from P acquiring system (efficient mobilization of P from the mineral phase) to P recycling systems (highly efficient cycling of P). Regarding P fluxes in soils and from soil to streamwater, this leads to the assumption that recycling systems may have developed strategies to minimize P losses. Further, not only the quantity but also the chemistry (P forms) of transported or accumulated P will differ between the ecosystems. In our project, we will therefore experimentally test the relevance of the two contrasting hypothetical nutritional strategies for P transport processes through the soil and into streamwater. As transport processes will occur especially during heavy rainfall events, when preferential flow pathways (PFPs) are connected, we will focus on identifying those subsurface transport paths. The chemical P fractionation in PFPs will be analyzed to draw conclusions on P accumulation and transport mechanism in soils differing in their availability of mineral bound P (SPP core sites). The second approach is an intensive streamwater monitoring to detect P losses from soil to water. The understanding of P transport processes and P fluxes at small catchment scale is fundamental for estimating the P exports of forest soils into streams. With a hydrological model we will simulate soil water fluxes and estimate P export fluxes for the different ecosystems based on these simulations.
Das Projekt "Extreme events in the past and future - A comparative assessment for the Hai He river and the Poyang lake basins" wird vom Umweltbundesamt gefördert und von Rheinische Friedrich-Wilhelms-Universität Bonn, Meteorologisches Institut durchgeführt. The impact of future climate change on land-use and water resource management is strongly dependent on the related changes in weather extremes. The future can only be assessed by the use of global climate models, which currently lack the necessary spatial resolution to represent such events. Moreover, global climate models are not able to incorporate all processes leading to extremes because of their low resolution. Thus downscaling of such runs is necessary, and only dynamical downscaling with high-resolution regional models is able to catch the necessary non-linear processes and process chains leading to extremes. The goal of this joint proposal is to provide estimates including their uncertainties of the behaviour of extreme weather events impacting land-use and water management for the 21st century for two climatically very different catchments, namely the Hai He river and the Poyang lake basins. To this goal we will first analyse the past of extreme events in both regions on the basis of observations and reanalysis data sets using state of the art extreme value statistics. Dynamical downscaling of global climate runs will be performed in order to evaluate the future of extreme events in the catchments. This necessitates first an evaluation of simulations of the current climate and its extremes by comparison with observations on a statistical basis. This will enable us to use the most appropriate regional climate model and to select the parametrisation setup most suitable for both regions, which might be different. While the Chinese partners will provide the observation data sets and perform the dynamical downscaling of global climate runs, the German partners will install the dynamical downscaling procedure at the Chinese partner institute, and generate the statistics of extremes both from observations and the simulations. The evaluation towards trends and uncertainties will be performed in close cooperation.
Das Projekt "Fire - climate feedback in the Earth System" wird vom Umweltbundesamt gefördert und von Max-Planck-Institut für Meteorologie durchgeführt. Fires are an integral Earth System process, which is controlled by climate and at the same time impacts climate in multiple ways. As such fires form a feedback mechanism in the Earth System, which might amplify or dampen climate change. At present this feedback is not well understood nor is it represented in current generation Earth System models used to study climate change. The proposed research project aims to quantify the fire-climate feedback by incorporating the integral role of fires into an Earth System Model (ESM). Together with improved observational based process understanding the project will analyze how fires have developed throughout Earth history and how single fire driven processes contribute to the overall fire climate impact. A mechanistic terrestrial biosphere fire model will be implemented into the ESM and fire mediated climate relevant processes will be coupled between the different ESM compartments, including the atmosphere, ocean and cryosphere. This cross-disciplinary research project will foster the understanding of past climate change and will hopefully allow a better assessment of human induced future climate change by further constraining the climate sensitivity of the Earth system.
Das Projekt "Sub project: Geochemistry of gases in seismogenic depths of the San Andreas Fault Zone" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum durchgeführt. The origin of gases and fluids in seismogenic depths of the San Andreas Fault (SAP), their composition, spatial distribution, temporal variations, migration mechanisms, as well as the link to seismic processes are only in part understood. We propose to perform gas and fluid studies on drill core, drill cutting, and drill mud gas from the SAFOD core drilling campaign in 2007, in order to gain quantitative information on the geochemistry of fluids and gases in seismogenic depths. Own drill-mud gas analysis from the SAFOD main hole (MH) revealed important information on the contribution of mantle-derived fluids to the total fluid inventory of the SAF and the migration of such fluids, and on the origin and distribution of the main non-atmospheric gaseous components on relatively large spatial scale. However, some questions addressed to gases at the SAF remained open: 1) the origin of the huge amounts of H2 in drill-mud gas found during drilling the SAFOD MH and 2) absolute gas concentrations and small-scale distribution of gases and fluids in fault zone rock which would help to understand fluid migration mechanisms at seismogenic depths. Drill-mud gas samples and drilled rock samples have been collected for investigations on isotopes (noble gases, (13C on CO2 and hydrocarbons, H/D on H2 and CH4) as well as mechanochemical gas synthesis. In combination with results from on-site experiments, this information provides better understanding of the behaviour of fluids and gases at seismogenic depths of the SAF.
Das Projekt "Sub project: Structural and temporal evolution of the Hawaiian plume: Constraints from noble gases in surface samples and the HSDP drill core" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum durchgeführt. Ocean Island Basalts (OIBs) produced by intraplate volcanoes such as e.g. the Hawaiian ones are often geochemically characterized by variable isotopic signatures due to sampling of different mantle reservoirs. These variations can occur over short distances on a very local scale. The aim of the Hawaii Scientific Drilling Project (HSDP) was to investigate the chemical and isotopic heterogeneity of a single volcano, Mauna Kea, to better constrain the temporal evolution of the Hawaiian mantle plume. In addition to this we are interested to study the Hawaiian mantle plume in time and space. Thus we propose to investigate the spatial structure of the Hawaiian plume using noble gas isotopes of samples from several volcanoes of the 'Kea chain'. Noble gas data, especially Ne data, from the Kea trend volcanoes are scarce. Those data have not only the great potential for resolving different geochemical reservoirs but also to deduce mantle dynamic and magmatic processes being involved in melt generation and evolution.
| Origin | Count |
|---|---|
| Bund | 472 |
| Type | Count |
|---|---|
| Förderprogramm | 472 |
| License | Count |
|---|---|
| offen | 472 |
| Language | Count |
|---|---|
| Deutsch | 472 |
| Englisch | 314 |
| Resource type | Count |
|---|---|
| Keine | 237 |
| Webseite | 235 |
| Topic | Count |
|---|---|
| Boden | 401 |
| Lebewesen & Lebensräume | 419 |
| Luft | 315 |
| Mensch & Umwelt | 472 |
| Wasser | 325 |
| Weitere | 472 |